TALLAHASSEE, Fla. -- Freshman Harrison Barnes' 3-pointer from the top of the key with 3 seconds to play gave No. 13 North Carolina a 72-70 victory at Florida State on Wednesday night.

John Henson had 19 points and 12 rebounds and Barnes added 18 points for the Tar Heels (23-6, 13-2 Atlantic Coast Conference), who won their sixth straight game overall and their fifth in a row on Florida State's court.

North Carolina took the lead midway through the second half and was up 67-60 on Kendall Marshall's 3-pointer with 3:59 left.

Florida State rallied to take a 70-69 lead with 18 seconds left on two free throws by Derwin Kitchen, who led the Seminoles (20-9, 10-5) with 13 points.

Florida State turned the ball over before getting off a final shot after Barnes' game-winner.

The Tar Heels can clinch the top seed in next week's ACC tournament win a win over No. 4 Duke on Saturday.

Leslie McDonald added 10 points for North Carolina, including two 3-pointers 43 seconds apart that gave the Tar Heels a 49-44 lead with 14:18 left.

Florida State led 38-37 after a first half that saw both teams shoot 16 of 31 from the field and had nine lead changes and nine ties.

Henson, a 6-foot-10 sophomore from Tampa, had a big first half with 12 points, six rebounds and three blocked shots while Florida State answered with strong play from its bench players, who outscored the Tar Heel reserves 20-5.

North Carolina shot 47.3 percent for the game and had a 39-28 rebound advantage.

One of those Seminole backups, freshman Ian Miller, nailed a 3-pointer from the corner midway through the first half that gave Florida State its largest lead of the game at 26-19.

Florida State was attempting to finish a perfect ACC season at home for the first time since coming into the conference for the 1991-92 season.

Barnes had 17 points and 10 rebounds in the Tar Heels' 89-69 home victory over Florida State 24 days ago.